The invention relates to a photographing apparatus, and more particularly, to such apparatus for use with a microscope.
A variety of photographing apparatus have been proposed and used in practice, but are found to be insufficient in their systematic capability. By way of example, a photographing apparatus for use with a microscope requires the following capabilities:
(a) The ability to take a picture under a flashlight from a xenon light, in addition to a tungsten or halogen lamp;
(b) The capability to permit the use of a variety of films including 35 mm film, 6 cm.times.9 cm Brownie film, instant photography film and 16 mm film;
(c) To permit either automatic or manual exposure;
(d) The provision of an intervalometer which controls the number of picture frames which are to be taken during a given period of time;
(e) The provision of a printer which records the photographing conditions, for example, film speed, a correction of a sample density distribution, an actual exposure period, a sample number or the like;
(f) The capability to calculate and display an expected exposure period;
(g) The ability to determine and display the remainder of the exposure period;
(h) To permit the display of an actual exposure period.
However, a conventional photographing apparatus for use with a microscope is provided with only part of the above capabilities.
In addition, a photographing apparatus for use with a microscope may be required to take a picture under a very weak or a very strong illumination of an object being photographed. In these circumstances, the failure of Bunsen-Roscoe's reciprocity law occurs, necessitating a corresponding correction. In such instance, the exposure period will increase, making it necessary to calculate and display an expected exposure period and the remainder of the exposure period. In the prior art, there has been no arrangement which provides an accurate display of such exposure periods in a digital manner.
When the exposure period increases for the reasons mentioned above, the brightness of an object being photographed may frequently change during the course of the photographing operation. It is also necessary to calculate an accurate, expected exposure period and the remainder of the exposure period if the brightness changes in such a manner. However, a conventional photographing apparatus which utilizes a stored and fixed photometric value is unable to provide an accurate indication of the expected exposure period under the varying illumination.